Congress remains a session until its members do what?

Recess. There are two types of recess. One is used routinely to recess for a period of time, usually over the summer or winter break. Congress then reconvenes once that break is over. Congress can also be recalled or reconvened during times of emergency. A Sine Die Recess occurs every two years when the congress has ended. That congress is recessed permanently and will not reconvene until the new members of congress are sworn in. After a Congress recesses Sine Die, all pending legislation on the calendar is disposed of and the calendar is cleared. Any legislation that has not been considered by that time, must begin the process all over again.